Drawing instrument



Z 1,651,504 c. BENNETT DRAWING INSTRUMENT Fild Oct. 27, 1925 WWII/111111110"- Patented Dec. 6, 1927.

' CHARLES BENNETT, 0F RICHMOND HILL, New YORK.

- DRAWING- INSTRUMENT;

Application filed October 27, 1925. serial No.z6 5,-1'59.

This invention relatesto drawinginstruments and more particularly to pens form'- ing parts thereof. It is adapted for use both in ri ht-linepens a-nd eompass pens as Well D as how pens.

In pens of this general character .itis the common practice to construct them with two blades, either one .or both of which are fiexi bleand with said blades'co-operates an adjusting screw working loosely through a perforation in one and threaded through the other. The tensioning of. the flexible blade is such that said blades normally tend to separate attheir free ends and adjustment of theserew the free or working ends of the pen are brought into the desired proximity to produce the adjustment necessary for the line of the desired width. In all. drawing instruments employing pens ofwhich I am aware, the foregoing principle of adjustment through the utilization of the adjusting screw has been the"universal: practice. In spiteofthe, generalusage of this construction, however, it is open to manydisadvantages among which ma be mentioned the all too frequent stripping ofthreads of the adjusting screw or the tapped hole inwhich it operates, the losing ofsaid screw andfrequently the inability toproperly replace the lost adjusting screw by a new one due tothe wide variety of. threads and screw sizes em ployed in the the: market;

lVith the foregoing mind,the primary objects of the present invention are to provide a greatly simplified adjustmentfor drawing pens, compasses and bow compasses which will beeconomical to manufacture, durable and thoroughly, efficient in use. I

Speaking generally, the present invention utilizes for the purpose of adjustment between the working points or] ends of the great number ofpens foundon blades, co-operating cam members mounted on the respective blades and normally main-- tained in Contact. with one another by suitable resilient means normally overcomingthe" tendency of the blades to spring apartr At-leastone of the cam members is supported on itsassociatedblade for rotationand is provided with a finger piecewhieh, when turned, exerts a; cam action upon the .00-

operating cam of'the other blade for the pur considerations in judgment of the draftsman, will produce I the line of the desired widt-h. In one of its preferred practical forms,- the pen, is made with a rigi d blade and a relatively resilient; blade, the two blades being associated; in such manner. that the latter will normally tend to retract or spring away from the rigidblade. On the flexible blade is mounted a-spring which 'ismanually movable into the position toovercome the inherent resil' iencyof the blade andforcethe free end of. said blade into contact with the corresponding end of the rigid blade. On either one of. the blades, preferably the flexible 'blade is mounted a fixed mandril and axial'align, ment therewith there is mounted on the rigid blade a suitable spindle. carrying between the two blades a cam and on the exterior of.

the blade a suitable finger piece. The face ofth'e cam aswellas the face ofthe' mandril are complementarily camshaped and through the action of the spring to which I have referred these cam faces are; maintained. at all times in abutting relation. It therefore followsthat the cam may be caused to revolve over the fixed face of the man'driland in so doing effect the adj ust-' i ment desired. In practice thereis sufiicient friction between the cam, itsspindle and the rigid :blade to maintainthecam against inadvertently shifting from any; position, in

ings and .appended'claims. v

'In the accompanying drawings, I have illustrated difierent practical embodiments of the present invention, but I wish it understood that these showings are for the purpose of illustration only and do not define the limits of. the invention. f

In said drawings: Figurel is a face view .of a right-line pen embodying the present invention. Figure 2 shows the pen illustrated in Figure 1 partly in elevation and partly in section on the line:22 of; Figure 1.

scription andfrom the accompanying draw- 7 Figure 3 is another view ofthe same pen and showing same as it appears on the side opposite that shown in Figure 1.

Figure t is the side elevation of the pen showing blades in relatively open position, as for cleaning or sharpening.

Figure 5 is a view similar to Figure 3 but showing the pen in the condition in which it is illustrated in Figure 4.

Figure 6 illustrates the invention as applied to a bow compass and also showing a slightly inoiflified form of the invention.

Referring to the drawings, and more particularly to the Figures 1. to 5 inclusive thereof. the right-line or bow pen as illustrated embodies a suitable handle 1 at one end of which is mounted a rigid blade 2 and a relatively flexible blade 3. It will be apparent from Figure 2 that the blade .3 is relatively rigid and is mounted rigidly on the handle 1. Blade 3, in contra-distinction. while mounted rigidly at itsbase on the handle, is provided intermediate its ends with a portion 4. of reduced cross section which imparts to this blade its resilient characteristics. The parts are so organized that the flexible blade 3 will normally spring away or retract from the rigid blade 2 and partake of the position shown in Figure 4.

Mounted either on the handle 1 or at the base of the blade 3 a spring 5 shown as a leaf spring. This spring 5 is mounted on the pin 6 for pivotal movement and is adapted to be moved from the retracted position of Figures 4: and 5, wherein it is disengaged from that portion of the blade 3 beyond the spring section 4, into the position of Figures 2 and 3, wherein it will bear upon the flexible blade 3 at the point be tween the spring section 4 and the free end of the flexible blade. In order to maintain the spring 5 from inadvertently shifting from this position into which it is adapted to be manually moved, said spring preferably has a protuberance 7 on its inner face and this protuberance is adapted to seat within the depression 8 formed on the top of the face of the blade 3. In practice. the protuberance T may be formed by punching out a projection from the body of the spring or by bending the spring or by placing a suitable protruding member thereon.

In any event, the spring 5 is made sulliciently heavy to overcome the tendency of the blade 3 to retract from the blade 2 and consequently such spring 5 to force the free end of the blade 3 into contact with the free end of the blade 2 as clearly shown in Figure Wounted on the blade 3 in rigid relation thereto is a suitable mandril 9 and mounted upon the blade coaxial with the maudril 9 is a spindle 10. This spindle is rotatably mount-- ed on the blade 9. and carries at its inner end a head 11, and at its outer end said spindle is provided with a finger piece 12.

tends at all times The face of the head 11 abuts the contiguous face of the mandril t) and these two faces, designated, respectively, 11 and 9", (see Figure are in the form of cam surfaces, i. e. are preferably cut on the slant. Accordingly, rotation of the piece 12 will cause the cam surface 11 to rotate over the sloping surface 9 of the fixed niandril 9 and in so doing the flexible blade 3 will be caused to move toward or away from the blade 2 for the purpose of obtaining the desired adjustment. The linger piece '12 is knurled to all'ord a finger grip and to allow it to be made relatively small while still peri'nittiirg it to be properly grasped.

'lhe eonstrui'rtion ilhntraled in l igure (i operates in substantially the same manner as that described in connection with Figures 1 to 5, but for the purpose of illustration the construction of Figure 6 is shown as associated with a bow compass. It differs structurally from the showing of Figures 1 to 5 mainly in the fact that the operating rotary cam. instead of being positioned exteriorly of the rigid blade positioned intermediate the mandril 9 and said blade, and the spindle 10 passed through a perforation in the blade provided at its outer end with a fixed collar forming the stop 14-. The leaf spring 15 riveted to the rigid blade 2 bears against the stop 14 and impels the stern of the spindle in an outward direction to bring the face of the linger piece tightly againstthe inner face of the rigid blade in order to in crease the friction between these parts, whereby there will be less liability of inadvertent shifting of the cam member 9 after it has been placed in the desired adjustment. In this connection it may be noted, from the structural standpoint, that the friction producing spring 15 may be either bifurcated to straddle the spindle and bear against the stop 14 or said spring may be perforated so that the spindle passes through such perforation with the stop exterior of the spring. In either event the mode of operation is the same.

I wish it ImtlGISlIOOtl, in this connection, that the pen. structure illustrated in Figure (3 including a spring for the augmenting of friction, may be applied if desired to rightline pens of the character shown in Figures 1 till 1 to 5 and, conversely, bow compasses may be made with pen parts constructed in the same manner as illustrated in Figures '1. to 5. In other words, the two distinct forms of the invention illustrated may be used interchangeably in pens, compasses or other instruments.

The compass construction, illustrated in Figure 6 is conventional, that is to say the bow portion of the compass with its adjusting nut, handle and needle point is made as heretofore.

tailed description that this invention embodies many novel peculiarities that it is unusually simple in construction and economirelatively slight pitch and are not abrupt in their operation but, in contra-distinction, will, when the finger pieceis'rotated, func tion with very fine adjustment and in a per fectly smooth manner. It will, of course, be understood that when it is desired to clean or sharpen the pen the leaf spring 5 can be readily swung from its normal position in Figures 2 and 3 to its inactive position in Figures 4: and 5 in order that the inherent resiliency of the flexible blade 3 may autogenously act to move it into the position of Figure 4. After the cleaning or sharpening operation, the parts may be returned to the co-operative relation of Figure 2 by simply pressing the blades together manually and moving the spring 5 into the position of Figure 2, whereupon the parts will return to the adjustment which they previously occupied. It is of practical importance that the present invention may be readily associated with or applied to pens previously employing the screw adjustment by discarding the adjusting screw and applying parts of the present invention thereto. 7 The foregoing detailed descri tion sets forth the invention in its preferre practical form, but the invention is to be understood as fully, commensurate'with the appended claims. 7

Having described my invention, what I claim as new and ters Patent is:

1. A drawing instrument embodying a pair of co-operating blades which are relati'vely movable with respect to one another,

means for normally impelling the free ends of the blades toward one another, and manually operable cam means for spacing the free ends of said blades the desired distance apart. V a

' 2. A drawing instrument embodying a pair of co operating blades one of which is relatively rigid and the other of which is relatively flexible, the flexible blade being tensioned tonormally tend to spring away from the rigid blade, a spring co-operating with the flexible blade to force it against its inherent tension in the direction of the rigid blade, and manually operable cam means for regulating the spacing between the free ends of said blades.

3. A drawing instrument embodying a pair of blades one of which is relatively rigid and the other of which is relatively flexible and is tensioned to normally tend to spring away from .therigid blade, a leaf spring pivotally mountedon the instrument desire to secureby Letthis 17th day of and normally occupying a position to exert tension on the flexible blade and force it inthe direction of the rigid blade, and manually operable cam means for regulating the space between the free ends of said blades, said spring being movable into a position to permit the flexible blade to autogenously move into a remote position with respect, to

the rigid blade.

4. A drawing instrument embodying a pair of. blades one of which is relatively rigid and the other of which is relatively flexible, means for normally impelling the flexible blade into position wherein its free end will engage the free end of the rigid blade, a mandril carried by one of said blades, and a manually operablecam carried by the other blade and engaging the mandril, the contacting portions of the man,

ually operable member and the mandril being of cam like formation whereby the rotation of the manually operable member will effect adjustment in the spacing of the free ends of the blades. V

5. A drawing instrument embodying a pair of blades one of which is relatively rigid and the other of which is relatively flexible, means for normally impelling the flexible blade into position wherein its free end Will engage the free end of the rigid blade, a mandril carried by one of said -blades, a manually operable cam carried by the other blade and engaging the man'- dril, the contact portions of the manually operable member and the mandril being of cam like formation whereby the rotation of the manually operable member will effectadjustment in the spacing of the free ends of theblades, and means for frictionally maintaining the manually operable member against inadvertent movement.

6. A drawing instrument embodying a relatively rigid blade, a relatively flexible blade tensioned to normallytend tospring away from the rigid blade, a leaf spring 'pivotally mounted on the instrument and having a protuberance adapted to engage with the depression in the flexible blade, said spring being of suflicient strength to force the flexible blade in the direction of the rigid blade, a mand'ril rigidly carried by one of the blades, a spindle rotatable in the other blade and aligned with respect to the mandril, a head carried by the spindle and engaging'with the mandril, a finger piece also carried by the spindle for operating same, and the contacting faces of the head and mandril being sloping, whereby the head may be rotated for thepurposeof regulating the spacing between the free. ends of the blades.

Signed at Brooklyn, New York, in the county of Kings and State of New York October A. D. 1925. CHARLES BENNETT. 

